(1) Field of the Invention
The present invention relates to a chirp indicator of ultrashort optical pulse which measures the chirp quantity of an optical pulse, and particularly relates to a chirp indicator of ultrashort optical pulse which measures the chirp quantity of an ultrashort optical pulse by performing optical correlation processing using sample light recorded as a hologram.
(2) Description of the Related Art
Conventionally, a correlation measurement method for measuring an ultrashort optical pulse with a gate pulse used as a reference is widely known in measuring the chirp quantity of an ultrashort optical pulse in the femtosecond domain (for example, see R. Trebino, et al., Rev. Sci. Instrum., 68(9) pp. 3277-3295 (1997); C. Iaconis, I. A. Walmsley, Opt. Lett., 23 (10) pp. 792-794 (1998); and T. Konishi, Y. Ichioka, Opt. Rev., 6 (6) pp. 507-512 (1999)).
However, there is a problem with such a conventional correlation measurement method in that the ultrashort optical pulse that is generally used as the reference cannot always be obtained. Moreover, when simply isolating a chirp, there is no need to perform detailed waveform measurement; matching processing is sufficient. However, realizing a reference to be used in matching processing in the time domain is difficult.